Packing ring



A. W. MORTON PACKING RING July 2, 19 5.

Filed Jan. 24, 1955 II b 1. Q

Patented .Fniy 2, 11%35 PATENT @FWQE mesne assignments, to 'iiheBartlett lliiaywardl Qompany, Baltimore, Md, a. corporation of MarylandApplication January 24, 1933, Serial No. 653,303

5 Claims.

This invention pertains to an improvement in packing rings and while thestructure is of general application it is especially designed for use inconnection with locomotives wherein the rings are subjected toconsiderable wear and have to be quite frequently renewed.

The main object of the present invention is to provide a ring structure,which, though simple, is nevertheless effective. in operation, readilyadapting itself to out-of-round cylinders and also readily seatingitself upon the side walls of a worn piston groove.

Another object of the invention is to produce a. ring composed of twoseries ofarcuate or segmental sections, which sections are of such formand so related that when forcedor urged outwardly as the piston passesover unequal diameters of the cylinder, the various sections of thepacking are also moved laterally away from each other and contact theside walls of the piston groove, sealing the groove against the passageof steam or other motive fluid and likewise preventing rocking ortipping of the ring and consequently diminishing the wear of the ringupon the walls of the groove.

A further object is to provide a structure which will prevent blow-by toa marked degree. The inner expander ring which is fiat in cross sectionand polygonal in outline, divides the space behind the segmental pistonring into separate compartments so that any leakage through a joint ofone series of segments will not travel around behind the ring to anyappreciable extent and pass out through a joint in the opposite series.

A still further object is to produce uniform pressure of the segmentsagainst the cylinder regardless of minor inequalities in the ring grooveon account of alternate contacts of the expander ring with the bottom ofthe ring groove and the individual segments of the piston ring. Thespring also tends to centralize the piston and cushion the same againstany tendency to slap.

The invention is illustrated in the annexed drawing wherein:

Fig. 1 is a sectional elevation showing a portion of a piston with thering of the present invention seated in the, groove of the piston;

Fig. 2, a. sectional elevation of the ring as viewed from the edgethereof;

Fig. 3, a perspective view of a number of segmental sections which go toform the ring and illustrating means for preventing undue relativerotative movement of the segments of one of the series with reference tothose of the other series ((Ci. filth-27) while still permittingfacewise movement of such series with reference to each other;

Fig. 4, a transverse sectional view taken on the line IV-IV of Fig. 1,the parts being upon an enlarged scale;

Fig. 5, a similar view showing a slightly modified form of ring insofaras the cylinder contacting face of the ring is concerned; and

Fig. 6, a perspective view illustrating the two series of arcuatesections forming a ring, the sections or one series being longer thanthose of the other, whereby aligning of the joints between the ends orthe sections of the two series is precluded to a greater or less extent.

Locomotive piston rings are subjected to considerable wear and have tobe replaced frequently. The ring forming the basis of this invention maybe readily placed within a piston groove and will seat itself, not onlyagainst the side walls of the groove but likewise against the face ofthe cylinder,-be the cylinder true or out-of-round.

The structure is such that the sections or segments of the two serieswhich stand in facewise relation to each other will readily accommodatethemselves to the inequalities of a cylinder and not only be forcedoutwardly toward the cylinder wall but, as the piston moves over unequaldiameters of the cylinder, the sections will also be forced laterallyinto contact with the side walls of the ring groove. In other words theparts are not secured to each other and are free to move relatively toeach other except, and only, as rotative movement of the segments of oneseries is restricted or limited with reference to the segments of theother series. In Fig. 6, however, even this means is not present.

Referring first to the structure shown in Figs. 1 to 4, it denotes thepiston having a ring-receiving groove, or grooves, ii. The ring in thisinstance is composed of two annuli, each annulus being produced from a.series of segmental or arcuate sections placed end to end, the sectionsof one annulus being denoted generally by I2 and those in theother by H.Each of these sections may be said to comprise a main body portionprovided'with a laterally extending flange, said flanges extending inopposite directions and being denoted respectively by l3 and l3 in thetwo series. The sections l2 are also formed with ribs or flanges llwhich extend toward the complemental members l2 in the other series andare designed to enter a channel or groove 15 formed in the adjacent faceof such members.

' As will be best seen upon reference to Figs. 2, 3, 4 and 5, the ribsll are tapered and the side walls of the groove or channel i5 are givena reverse taper. It will likewise be seen that the rib is of suchdimension that it does not fully fill the groove. A

When seated within an unworn piston groove the segments l2 and 52 of thetwo series will stand in close facewise relation with but slightclearance between such segments and likewise between them and the wallof the ring groove.

Seated within the piston groove, and bearing:

against the various segments throughout both series which compose thering is an expander spring i6. Said member will preferably be formed soas to present a series of long sections which bear against the bottom ofthe ring-receiving groove and shorter sections which bear against theinner face of the ring, the spring being of such width as to bear uponboth series of sections and yet not wide enough to contact and bindagainst the side walls of the groove. Such a spring insures asubstantially even outward pressure upon the various sections of whichthe ring is composed.

As will be seen upon reference to Fig. 1, the ends of the springs arepreferably twisted in opposite directions;this with a view of having oneend catch in a joint between two segments while the other end willdoubtless catch in a rough place in the piston groove. By twisting eachend of the spring, and this in opposite directions, any tendency of thespring to cant the overlying segmental sections of the ring isminimized. This arrangement also prevents or reduces to a marked degreerelative rotary motion or movement between the spring and the piston andthe spring and the packing or ring.

To prevent aligning of the joints between the segments of the two annulithere may be provided a pin, as H, secured in one of the segments of oneof the annuli and extending freely through an opening I8 formed in .theopposite segment in .the other annulus. The pin and opening will ofcourse be so positioned relative to their respective segments as tothrow the joints of the segments of the annuli out of alignment. The pinis freely movable in the opening l8, hence the parts are notfastenedtogether but have a floating relation and consequently are freeto move both laterally toward and from each other and consequentlytoward and from the side walls of the ring-receiving groove.- Thetwoannuli also may have slight radial and circumferential movementsrelatively to 'each other due to the floating connection insured by thepin passing into the enlarged opening. Thus the individual segments mayseat independently of one another against the cylinder wall and/oragainst the side walls of the piston roove The spring l6 will tend tomove the segments outwardly and, with the aid of steam pressure whichpasses beneath the packing, the various segments of the packing will beheld tightly against the cylinder and when the piston passes overunequal portions of the cylinder, the tapered formation of the ribs-ortongue l4 and groove l5will cause the segments of the ring to not onlybe moved outwardly but laterally as well. As will be seen upon referenceto the drawing, and more particularly Figs. 1, 4 and 5,. spring I6 is ofa width such that its edges do not contact the side walls of thering-receiving groove, but underlie the major portion of the two seriesof segments. This permits a slight twist of the spring when the segmentsand/or cylinder become worn, so that the spring will function at alltimes to move the segments outwardly with relation to each other and tothe cylinder with which they cooperate, particularly when the cylinderis out of round or bellied. This brings the cylinder-contacting face ofthe ring into proper sealing relation with the wall of the cylinder and,through the wedging action, forces the segments laterally into closecontact with the side walls of the piston groove. This action isspecially advantageous where the ring is positioned in a ring-receivinggroove which has become worn and the side walls of which stand in adiverging relation toward the outer face or side of the piston. It hasbeen found in actual practice that by reason of the wedging relation ofthe parts and the forcing of the same outwardly by the spring l6 that afull cylinder-contacting bearing surface is effected after the ring hasseated and instead of wearing round, as is usual with piston rings, theouter faces of the segments will trace a straight line from side to sideof the ring.

Locomotive cylinders present somewhat peculiar conditions when'it comesto installing piston rings which will properly function therewith. Forinstance, in a locomotive cylinder where the steam is admitted at oneend through a port at high pressure and this steam moves the piston awayfrom that end of the cylindenthe pressure in the cylinder, as will beappreciated, gradually diminishes, and at the opposite end of the strokeof the piston an exhaust port is opened and the pressure drops to zero.-However, when steam is admitted to both ends of a locomotive cylinderand, consequently, on opposite sides of the piston, pressure rapidlybuilds up and moves the piston back to the end of the cylinder. fromwhich it originally started, and as the piston trave1s,-the pressure inthat part of the cylinder gradually diminishes until the piston is atthe extreme end of the stroke and the other exhaust port is opened andthe pressure drops to zero.

The pressure diagram in the cylinder of a double acting locomotiveengine would, therefore, trace an indicator-diagram something on theorder of an hour glass or a spool. In short, the pressure diagram wouldshow excessive pressure at either end of the cylinder, and a much lowerpressure in the center of the cylinder.

It has been found, in practice, that locomotive cylinders wear in exactaccordance with the pressure diagram, or, in other words, the indicatorcard. Consequently, the packing rings have to move in and out of thepiston grooves as the piston travels through the length of its stroke,in order to maintainproper contact with the cylinder wall. The amount ofthis in and out travel of the packing ring is frequently as great asonequarter of an inch from the smallest diameter of the cylinder whichis in the longitudinal center to the maximum diameter of the cylinder ateither end.

locomotive cylinder, there is another characteristic that is almost asimportant when it comes to the function of the piston-rings. This is dueto the fact that the piston and cylinders are horizontally disposed and,consequently, due to the weight of the piston and packing rings restingon the bottom of the cylinder, there is a tendency to wear the cylinderout of round and oversize on the vertical dimension. Sometimes, however,due to the misalignment of thejspiston crosshead. a severe thrustcausesthe cylinder to wear bellied" In addition to this characteristic wear ofa,

or out of round in a different direction. The gen- I eralcharacteristic, however, is for the cylinder aooaaos to wear large oneither end and also larger on the vertical dimension than on thehorizontal dimension.

It is, therefore, quite obvious that the average locomotive cylinderwill be of unequal diameter throughout, and hence the packingnecessarily has to move in and out of the piston groove to follow thecontours or irregularities of such a cylinder, if the packing isdesigned to make a cylinder contact at all times. The packing of thepresent case functions in this manner.

It is to be kept in mind that the packing oi the present case has anexpander placed between the piston and the packing so as to hold thepacking in contact with the cylinder at all times; this regardless ofthe out of round condition or tapered condition of the cylinder. Apacking of the type herein disclosed follows the contour of the cylinderand the inequalities or out of roundness of the cylinder, and,consequently, is continually moving in and out of the piston groove asthe piston moves back and forth throughout its stroke.

As the piston moves from the smaller portion of the cylinder toward thelarger part of the cylinder, it follows that the leading section of thepacking moves into the larger part of the cylinder a little in advanceof the following or trailing section of the packing and, therefore, theleading section of the packing moves outwardly with reference to thetrailing section of the packing as the piston moves from the smaller tothe larger part of the cylinder. This outward movement of one section ofthe packing with reference to the opposite section of the packing, whichwould he helped by means of a slight twist in the spring underneath thepacking, and also due to steam pressure underneath the packing orunderneath the flange of the packing holding the packing out against thecylinder, will also cause the packing to move sideways in thepiston-groove, were the groove flared or enlarged to such an extent asto allow this side movement. Grooves, of course, become flared owing towear. Then, on account of the tapered tongue and grooved portions of theopposing sections of packing, there would be a tendency to wedge theopposing sections of the packing sidewise as they move in and outthrough different diameters of the cylinder with reference to oneanother and with reference to the piston groove.

This irregularity of movement of the various sections or segments of thepacking produces an operating condition which causes the packing to bearlaterally against the lands of the piston groove, and at the same time,against the cylinder itself. Moreover, while the tapered tongue andgroove construction keeps the packing tight against the sides of thepiston groove, it also has the function of preventing the ring segmentsfrom catching in the counterbore should the piston over-travel.

The provision of the oppositely disposed lateral flanges l3 and ldproduces a somewhat extended bearing surface. Their presence, however,is not essential and in Fig. 5 ring structures wherein they are omittedare shown. The structure is otherwise the same as that above described.

It is of course conceivable that the segments of the two annuli may varyin number so as to inhibit alignment of segment joints. Thus, as seen inFig. 6, the upper annulus is produced from six segments designated a, b,c, d, e and. f and the lower one of five segments designated a, h, c, dand e. By producing the annuli with a variation of one in the number ofsegments employed it will be readily perceived that at no time can morethan one joint between segment ends in one annulus coincide with asimilar joint in the other. I

initially positioned in a ring groove with the joints in nonregisteringrelation, the expander spring acting as above specified will tend toprevent relative rotative movement of the annuli and consequently tomaintain the parts as -positioned.

A cross section of the ring as shown in Fig. d appears as in Fig. 5,with the inner expander spring positioned behind the ring in theringreceiving groove in the piston.

What is claimed is: I,

l. in combination with a piston having a ring receiving groove; a pistonring mounted in said groove, said ring embodying two series of arcuatecylinder-contacting sections, the sections of each series arranged endtoend and said series lying in iacewise relation to each other withinsaid groove and free to move laterally throughout each series away fromeach other toward the adjacent side wall of the ring groove and also mayahle radially therein; spring eons located within the groove to the rearof and bearing upon the sections of each series and urging all oil suchsections outwardly of the groove, said spring being flat in crosssection; and means formed upon the opposed faces of the arcuate sectionsof each se ries to cause the e to move axially with r spect to the otherunder the uence oi said spring means and likewise limiting the relativeradial movement of one series with reference to the other.

2.1m combination with a piston having a ringreceiving groove; a pistonring mounted in said groove, said ring embodying two series oi arcuatecylinder-contacting sections, the sections oil each series arranged endto end and said series lying in facewise relation to each other withinsaid groove and free to move throughout each series away from each othertoward the adjacent side wall of the ring groove and also being indalmovable therein; expander spg acting directly on each section and urgingall of said sections outwardly of the groove; and oppositely disposedcoacting means on the adjacent faces oi the series of said scents whichunder theinfiuence of said expander efiects lateral movemerit of thesegments oi each series toward the adjacent side wall of the groove asthe sections are moved outwardly oi the groove, said means alsopermitting a limited ral movement oi said segments of each of the seriesindependent oi.any radial movement of the segments oi the other series.

3. A piston ring comprising at least two cylinder-contacting annulilying in iacewise relation and free to move relatively to one anotherthroughout. each annulus toward and from each other, and likewise freeto move radially of a piston groove in which they may be coated,independently oi each other, each annulus being formed from a pluralityof arcuate members arranged in end to end relation, the opposing sidefaces of each of the arcuate members oi? the annuli being provided withcomplemental interen= gaging, coacting wedging i, s laces ha a clearancetherebetween permitting-l radial movement oi the segments of one oi theannuli with reference to those of the other.

a. The cbination with a piston ha a groove therein, of a piston sted msaid groove and comprising two sets of arcuate cylintier-contactingsections, the sections of each set standing in end to end relation;means for preventing the joints between the sections of one set fromlining up with the joints between sections of the other set butpermitting relative and free axial movement of all of the sections; anexpander spring polygonal in outline bearing against the innermost faceof each and all of the sections of each set of sections and likewisebearing against the bottom of the ring groove to urge all of the saidsections radially outwardly of the groove and forming a plurality ofspaced chambers behind the ring sections; and means formed integral withthe sections and upon the opposed faces of each series for causing axialmovement of the sections within the groove as i the sections are urgedin an outward radial ditacting annuli lying in facewise relation andfree to move relatively to one another throughout each annulus towardand from each other and radially of the groove, each annulus beingformed of a plurality of arcuate members standing in end to endrelation, one face of the arcuate members of one annulus being providedwith a wedgeshaped rib extending outwardly therefrom and into a channelor groove of complemental contour formed in the opposing face of thearcuate members of the other annulus, there being clearance between saidgroove and the rib to permit relative radial movement; and a springunderlying all of said arcuate members and acting to move the ring as" awhole outwardly and the annuli with reference to each other, andconsequently toward the side walls of the ring groove by reason of thespreading action ofthe rib and groove construction aforesaid as thepiston moves through a restricted or out-of-round portion of 20 thecylinder.

- ALLEN W. MORTON.

